Smoke erupted from the enemy guns, followed by a roar like thunder as several ships opened fire on Belleisle at once. Spars came crashing down. Men screamed. Seeing the carnage, 1st Lt. Ebenezer Geale suggested to Captain Hargood that he swing round and fire a broadside, if only to throw up a smoke screen. Hargood's reply rang out across the deck. "We are ordered to go through the line, and go through she shall, by God!" Paul Nicolas held his breath and tried not to think about lying down.

Britain had been at war with France off and on since 1793. There was a brief peace in 1802, but a year later hostilities flared again. The Napoleonic Wars, as they became known, were a new kind of conflict: a war of ideology prosecuted in a spirit of deep animosity. For Nelson, Napoleon represented what Joseph Stalin—or Osama bin Laden—would mean to our age. Nelson passionately believed he had been called by his country, and by God, to defend England from tyranny.

By the summer of 1805, Napoleon had massed 90,000 troops in Boulogne for an invasion across the English Channel. But he had yet to assemble the naval power to protect his troops during a crossing. "England was in the middle of a total war for national survival," says Andrew Lambert, a professor of naval history at King's College London. "More taxes were raised per capita in the war against Napoleon than in the war against Hitler. For Nelson, the French were the enemy, and they had to be annihilated."

Annihilate was one of Nelson's favorite words. "It is annihilation that the country wants, not merely a splendid victory," he told his officers before the Battle of Trafalgar. The word was almost certainly on his lips as he paced the quarterdeck of Victory that morning, with his closest friend, the ship's captain, Thomas Masterman Hardy. They made a curious pair. Hardy was six feet four (1.8 meters and ten centimeters), a burly Dorset man of farming stock. Nelson was five feet six (1.5 meters and 15 centimeters), narrow-shouldered and built like a ballet dancer.

At the age of 47, Nelson was the most famous British naval commander since Sir Francis Drake. He had won three major battles and fought 50 other engagements, more than any admiral in the history of the Royal Navy. His highly publicized—and adulterous—love affair with Emma Hamilton, a British diplomat's wife Nelson had met in Naples, only added to his star wattage. "Nelson was the first great modern hero," says Tom Pocock, a Nelson biographer and former war correspondent. "Everyone knew the stories of his battles, and the story of Emma. He had toured Britain a lot. There were pictures of him everywhere. He was the first celebrity of the modern kind. He was everyman and superman."